> There were a million Doom clones, none of which were as good as Doom.
Sorry to take this on a tangent, but the problem with Doom clones isn't that they aren't as good as Doom, it is that Doom already exists and is known to the audience. If you've had your mind blown by Doom, playing a 10% better version of Doom isn't going to blow your mind again, it is going to merely be a fun experience. Many people won't even bother to try that 10% better Doom clone, since all they'll see is a clone of something they already tried.
To add, cloning is one thing, but a lot of games - including id's own games - iterated on the formula, leading to the genre of first-person shooters like Quake, Unreal, Half-Life, Medal of Honor, Halo, Bioshock, etc.
That is, clones rarely work, but evolutions do. Stardew Valley on the surface can be considered a Harvest Moon clone, but it iterated on the formula, leading to a lot of attempts at casual farm games from many different competitors. Minecraft was an Infiniminer clone (or inspired by?) and iterated on the idea. Fortnite was a PUBG clone which was a DayZ clone.
Sorry to take this on a tangent, but the problem with Doom clones isn't that they aren't as good as Doom, it is that Doom already exists and is known to the audience. If you've had your mind blown by Doom, playing a 10% better version of Doom isn't going to blow your mind again, it is going to merely be a fun experience. Many people won't even bother to try that 10% better Doom clone, since all they'll see is a clone of something they already tried.